WO2013026336A1

WO2013026336A1 - Method for path detection and node

Info

Publication number: WO2013026336A1
Application number: PCT/CN2012/078759
Authority: WO
Inventors: 郑直; 焦欣文; 金利忠
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-08-24
Filing date: 2012-07-17
Publication date: 2013-02-28
Also published as: RU2574812C9; CN102957573A; IN2014CN01369A; RU2574812C2; CN102957573B; RU2014111057A; BR112014004300A2

Abstract

A method for path detection and a node. The method comprises: an initiating node sending an echo request packet to a detecting node, carrying address list information, the address list information comprising the address of the initiating node; the detecting node checking whether a node address in the address list information carried in the received echo request packet is reachable, and using a found reachable address as a destination address of an echo replay packet; the detecting node adding address information thereof to the address list information carried in the echo replay packet to be returned. The node comprises a request packet sending module, a searching module, and a replay module. When the node does not have a reachable route of a head node, other nodes on an LSP, through which the packet passes, may be found according to the address list information carried in the echo request packet, and the echo replay packet is transferred to the initiating node by relaying, thereby increasing the success rate of tracing a route.

Description

Method and node for implementing path detection

Technical field

The present invention relates to network communication technologies, and in particular, to a method and a node for implementing path detection in a network based on MPLS technology.

Background technique

Multi-Protocol Label Switching (MPLS) Label Switching Path (LSP) Ping technology is an effective operation management and maintenance (OAM) technology that enables connectivity detection and hop-by-hop fault location. And can verify the consistency of the control plane and the data plane.

In the Internet Engineering Task Force (IETF, RFC4379), the MPLS LSP ping technology is described in detail: The echo request message is sent by the head node along the forwarding path of the service, on the LSP. The detecting node performs processing to return an echo reply (Echo Reply) packet to implement LSP connectivity detection or hop-by-hop positioning of the LSP fault. In the return mode of the echo reply packet, the most common one is that the echo reply packet is forwarded to the head node through the IP route.

However, the detection node that responds to the echo reply message is not a reachable route that always has a head node. In many scenarios, because the network administrator needs to properly control the distribution of routes, other nodes on the LSP do not reach the forwarding route of the head node. For example, for an LSP of a cross-domain autonomous system (AS), nodes of different ASs do not have routes to each other; or in a seamless MPLS scenario, nodes of different routing areas do not have routes to each other. . The IETF draft draft-ietf-mpls-interas-lspping-00 describes a scenario in which ASBRs control route distribution between different ASs by means of a mechanical recording autonomous system border router (ASBR). The detection node cannot reply to the situation where the head node detects the response message. However, for a more general scenario where the detection node has no head node reachable route, the solution cannot be solved.

Summary of the invention The technical problem to be solved by the embodiments of the present invention is to provide a method and a node for implementing path detection, which can complete path detection more flexibly and quickly.

In order to solve the above technical problem, the following technical solutions are used in the embodiment of the present invention:

A method for implementing path detection includes:

The initiating node sends a response request message carrying the address list information to the detecting node, where the address list information includes the originating node address;

The detecting node that receives the response request message checks whether the node address in the address list information carried in the response request message is reachable, and uses the found reachable address as the destination address of the response response message; The address information of the node is added to the address list information, and the response response message carrying the address information of the node is sent to the destination address.

Optionally, the step of the sending node sending the response request message carrying the address list information to the detecting node includes:

The initiating node carries the address list information in the first response request message that is sent, and the first address in the address list information carried in the first response request message is the originating node address.

The initiating node sends the nth response request message carrying the address list information, and if the initiating node receives the response response message fed back by the destination node of the response request message, the n+1th response request is sent. And transmitting, in the message, the address list information in the response response message; if the originating node does not receive the response response of the destination node fed back the response request message within a predetermined time, the sending response is When n+1 responds to the request message, the nth response request carries the address list information in the message.

Optionally, the step of checking whether the node address in the address list information carried in the response request message is reachable includes: searching, starting from the first address, whether the node address in the address list information carried in the response request message is Reachable.

Optionally, the step of using the found reachable address as the destination address of the response response message includes:

The first reachable address found is the destination address of the response reply message. Optionally, the method further includes:

The detecting node that receives the response response message checks whether the node address in the address list information carried in the response response message is reachable, and updates the destination address of the response response message to the found reachable address, to the destination. The address sends the response response message carrying the address list information.

Optionally, the step of checking whether the node address in the address list information carried in the response response message is reachable includes: searching, starting from the first address, whether the node address in the address list information carried in the response response message is in order Reachable.

Optionally, the step of updating the destination address of the response response message to the found reachable address includes:

The destination address of the response response message is updated to the first reachable address found.

Optionally, the step of the detecting node adding the address information of the local node to the address list information includes:

The detecting node deletes the address information after the reachable address found in the address list information, and inserts the address of the node after the reachable address.

Optionally, all address list information is encapsulated in TLV form.

Optionally, the addresses in all the address list information are loopback addresses.

Optionally, the initiating node is a head node of the LSP, and the detecting node includes other nodes on the LSP except the head node.

A path detection node includes a request message sending module, a searching module, and a reply module, wherein:

The request message sending module is configured to: when the node is the initiating node, send a response request message carrying the address list information to the detecting node, where the address list information includes the starting node address;

The searching module is configured to: when the node is a detecting node, check whether the node address in the address list information carried in the received response request message is reachable, and find the reachable address as the response response^ The destination address of the text; The replying module is configured to: when the node is used as a detecting node, add the local node address information to the address list information, and send a response response message carrying the local node address information to the destination address.

Optionally, the request message sending module is configured to send a response request message carrying the address list information to the detecting node in the following manner:

When the first response request message is sent, the first response request message carries the address list information, and the first address in the address list information carried in the first response request message is the originating node address;

When the n+1th response request message is sent, if the node receives the response response message fed back by the destination node of the nth response request message, the node carries the message in the (n+1)th response request message. The address list information in the response response message; if the node does not receive the response response message fed back by the destination node of the nth response request message within a predetermined time, the n+1th response request message is received. The address list information in the nth response request message is carried.

Optionally, the searching module is configured to check whether the node address in the address list information carried in the response request message is reachable according to the following manner:

The address of the node in the address list information carried in the response request message is searchable in order from the first address.

Optionally, the searching module is configured to use the following method to determine the reachable address as the response destination address:

The first reachable address that is found is used as the destination address of the response response message.

Optionally, the node further includes a forwarding module, where:

The forwarding module is configured to: after the node receives the response response message, check whether the node address in the address list information carried in the response response message is reachable, and update the destination address of the response response message to The reachable address is found, and a response response message carrying the address list information is sent to the destination address.

Optionally, the forwarding module is configured to check whether the node address in the address list information carried in the response response message is reachable according to the following manner:

Searching for the node in the address list information carried in the response response message sequentially from the first address Whether the address is reachable.

Optionally, the forwarding module is configured to update the destination address of the response response message to the found reachable address in the following manner:

Optionally, the reply module is configured to add the node address information to the address list information in the following manner:

The address information after the reachable address found in the address list information is deleted, and the address of the node is inserted after the reachable address.

Compared with the related art, the embodiment of the present invention has the following advantages: When the node responds to the response request packet of the LSP ping, and the reachable route of the head node is not available, the information can be found by responding to the address list information carried in the request packet. The other nodes on the LSP passing through the packet transmit the response response message to the head node in a relay manner, thereby improving the success rate of the tracking route. BRIEF abstract

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings to be used in the embodiments will be briefly described below. It is obvious that the drawings described below are only some embodiments of the present invention, which are common in the art. For the skilled person, other drawings can be obtained from these drawings without any creative work.

Figure 1 shows one of the flow chart of LSP path detection.

Figure 2 is the second flow chart of the LSP path detection;

Figure 3 is a schematic diagram of a node structure;

Figure 4 is a scenario diagram of an LSP across a routing area;

Figure 5 is a flowchart of Embodiment 1 of the present invention;

Figure 6 is a flow chart of Embodiment 2 of the present invention. Preferred embodiment of the invention

To solve the above technical problem, the embodiment of the present invention provides the following technical solutions. As shown in FIG. 1, the LSP path detection method includes the following steps:

The initiating node sends a response request message to the detecting node, where the address information is included, where the address list information includes the originating node address;

The detecting node checks whether the address of the node in the address list information carried in the received response request message is reachable, and uses the found reachable address as the destination address of the response response message;

The detecting node adds the address information of the node to the address list information and carries it in the response response message of the reply.

The LSP path detection method further includes: when the detecting node receives the response response message, checking whether the node address in the address list information carried in the response response message is reachable, and updating the destination address of the response response message to the search The reachable address to which the response response message carrying the address list information is sent to the destination address.

In the process of performing LSP traceroute in the MPLS-based network, the initiating node is the head node of the LSP, and the detecting node includes other nodes except the head node on the LSP, including the intermediate node and the last node (or the tail node). In the case that the detection node has no reachable route to the head node, the following technical solution is adopted to implement the detection response message to be forwarded to the head node by means of relay, as shown in FIG. 2:

Step 101: In an LSP path detection process, the head node carries address list information in the response request message, where the address list information includes a head node address;

The processing of the head node is divided into the following two cases:

The first node carries the address list information in the first response request message sent by the first node, and the first address in the address list information carried in the first response request message is the head node address;

The head node sends the nth response request message carrying the address list information. If the head node receives the response response message fed back by the destination node of the response request message, the n+1th response request message is sent. And carrying the address list information in the response response message; if the head node does not receive the response response message fed back by the destination node of the response request message, sending the n+1th The address list information in the nth response request message is carried in response to the request message. n > 2.

Step 102: After receiving the response request message, the other node except the head node on the LSP checks whether the node address in the address list information carried in the response request message is reachable, and finds the reachable address as a response response. The destination address of the 3⁄4 text, the address of the node is added to the address list information, and the address list information is carried when replying the response response message;

When other nodes except the head node on the LSP check the node address in the address list information carried in the response request message, they are usually searched in order, especially when the first address in the address list information is the head node address, from the first address. Start looking in order to return a response response message faster.

Optionally, other nodes on the LSP except the head node will find the first reachable address as the destination address of the response response message.

When other nodes on the LSP except the head node add the address of the node to the address list information, you can use the sequential addition method. In other embodiments, the node other than the head node on the LSP may also delete the address information after the reachable address found in the address list information, and then insert the address of the node after the reachable address. The address information after the reachable address is deleted, which can make the address list information smaller and save transmission resources. On the other hand, the path indicated in the address list information can be better.

Step 103: After receiving the response response message, the intermediate node on the LSP checks whether the node address in the address list information carried in the response response message is reachable, and updates the destination address of the response response message to the found one. Address, send a response with the address list information response > 3⁄4 text.

When the intermediate node on the LSP checks whether the node address in the address list information carried in the response response message is reachable, the intermediate node usually uses the sequential search method.

Optionally, the intermediate node on the LSP updates the destination address of the response response message to the first reachable address that is found.

Optionally, the address list information in the foregoing step is encapsulated by a type/length/value (TLV, Type/Length/Value), and the address in the address list information is a loopback address.

The node implementing the above method, as shown in FIG. 3, includes a request message sending module 31, a search mode Block 32 and reply module 33, wherein:

The request message sending module 31 is configured to: when the node is an initiating node, send a response request message to the detecting node, where the address list information is carried, where the address list information includes an initiating node address;

The searching module 32 is configured to: when the node is a detecting node, check whether the node address in the address list information carried in the received response request message is reachable, and use the found reachable address as the response response message. Destination address

The reply module 33 is configured to: when the node is used as a detection node, add the address information of the node to the address list information, and carry it in the response response of the reply>3⁄4.

Optionally, the request message sending module 31 is configured to send a response request message to the detecting node in the following manner, where the address list information is carried, where the address list information includes an originating node address:

When the n+1th response request message is sent, if the node receives the response response message fed back by the destination node of the nth response request message, the node carries the message in the (n+1)th response request message. The address list information in the response response message; if the node does not receive the response response message fed back by the destination node of the nth response request message, the nth response request message carries the nth Respond to the address list information in the request message.

Optionally, the searching module 32 is configured to use the following reachable address as the destination address of the response response message in the following manner: the first reachable address that is found is used as the destination address of the response response message. .

Optionally, the foregoing node further includes: a forwarding module 34, configured to: after the node receives the response response message, check whether the node address in the address list information carried in the response response message is reachable, The destination address of the response response message is updated to the found reachable address, and a response response message carrying the address list information is sent to the destination address.

The forwarding module 34 is configured to: further change the destination address of the response response message in the following manner Newly found reachable address: Update the destination address of the response response "3⁄4" to the first reachable address found.

Optionally, the reply module 33 is configured to add the local address information to the address list information in the following manner: deleting the address information after the reachable address found in the address list information, and inserting the address after the reachable address Node address.

In order to make the objects, the technical solutions and the advantages of the present invention more clearly, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments of the present application may be arbitrarily combined with each other.

In the following embodiments, the address list information is implemented in an address group manner.

Example 1

As shown in Figure 4, nodes a, b, c, and d form an LSP across the routing area. Head node a and node c, d are in different routing areas, and node b serves as the area boundary node (ABR) of the two areas. Controls the isolation of routing information between two areas, that is, a and c in different areas, and no reachable routing information between the a and d.

In this embodiment, all nodes on the LSP in Figure 4 are nodes having the trace routing function described herein. The trace routing process is shown in Figure 5 and includes the following steps:

Step 201: The head node a sends an LSP traceroute request, that is, an echo request message, and the carried address group only includes its own routable address, and the TTL label time to live (TTL, Time To Live) is set to 1;

Step 202: The node b processes the echo request packet, and checks whether the address in the address group is reachable, and finds that the address of the first address information, that is, the address of the head node a is reachable, and adds the address information of the node in the address group, and The modified address group information is placed in the echo reply message and sent back to the head node a;

The data structure of the address group information is as shown in Table 1. The address group can be encapsulated by means of TLV, and the address of the node is carried in the data part of the value. The address of the node 1 is a routable address of the head node, which is usually the loopback address of the head node, and the subsequent addresses are added or deleted as needed. Table 1

Type (address group type) Length (length)

Node 1 IP Address

Node n IP Address

Step 203: The head node a receives the echo reply packet sent by the node b, and copies the address group to the next echo request; sends an echo request packet, and the TTL of the LSP label is set to 2;

Step 204: The node c processes the echo request packet, and sequentially checks whether the address in the address group is reachable (in this case, the address group includes the address information of the head node a and the address information of the node b), and the node c finds the route to the head node a. Unreachable, continue to check whether the address of the node b is reachable. When the route to the node b is found to be reachable, the address of the node b is used as the destination address of the echo reply, and the address of the node is added to the node b of the address group information. After the address, the echo reply packet is sent, and the echo reply packet carries the modified address group information.

Step 205: Node b receives the echo reply packet, finds the address in the address group, finds that there is a reachable route to the head node a, and forwards the echo reply to the head node a;

Step 206: The head node a receives the echo reply packet, copies the address group to the next echo request, and sends an echo request packet, and the LSP label TTL is set to 3; Step 207: The tail node d processes the echo request. The packet does not find the reachable route of the head node a. The address in the address group is checked in sequence (the address group includes the address information of the head node a, the node b, and the node c), and the reachability of the node b is found. Route; the address of b is used as the destination address of the echo reply, the address of the node c after the address of the node b is deleted, and the address of the node c is added to the address group as the next address after the node b, and an echo reply message is sent. Carrying the newly modified address group information in the echo reply message;

Step 208: The node b receives the echo reply packet, finds the address in the address group, and finds that there is a reachable route to the head node a, and forwards the echo reply message to the head node a;

Step 209: The head node a receives the echo reply packet and completes the process of the LSP traceroute. Example 2

This embodiment is still described by taking the LSP shown in FIG. 4 as an example. Unlike the first embodiment, the node c in this embodiment does not have the trace routing function described herein. The trace routing process is shown in Figure 6, and includes the following steps:

Step 301: The head node a sends an echo request message, and the carried address group only includes its own routable address, and the TTL of the LSP label is set to 1;

Step 302: The node b processes the echo request packet, and checks whether the address in the address group is reachable. The reachable route of the end node a is found, and the echo reply is returned to a, and the address is carried in the address group carried by the echo reply. The address of the node;

Step 303: The head node a receives the echo reply message sent by the node b, and copies the address group to the next echo request; sends an echo request message, and the TTL of the LSP label is set to 2;

Step 304: The node c processes the echo request message. Since the node c cannot identify the address group information carried in the echo request message and does not have the address information of the head node a, it cannot send the echo reply message to the head node a.

Step 305: The head node a does not receive the echo reply packet, and after waiting for a certain period of time, copies the address group carried in the echo request ^ text of the last LSP tag with the TTL value of 2 to the next sent echo request. Send a new echo request packet, and set the TTL of the LSP label to 3.

Step 306: The tail node d processes the echo request packet, and checks whether the address in the address group is reachable. The reachable route of the head node a is not found. The address of the address group is searched backward from the address of the head node, and it is found that The reachable route of the node b; the address of the b is used as the destination address of the echo reply, and the address of the node is added to the address group as the next record, and an echo reply message is sent, and the echo reply message carries the modified Address group information;

Step 307: The node b receives the echo reply packet, finds the address in the address group, and finds that there is a reachable route to the head node a, and forwards the echo reply message to the head node a;

Step 308: The head node a receives the echo reply packet and completes the process of the LSP traceroute. The above embodiment is advertised to the detecting node by carrying the reachable path information in the echo request, so that the echo reply message replied by the detecting node can be forwarded to other nodes on the LSP, and finally forwarded to the head node by means of relay.

In addition to the manner in which the head node automatically adds the address list information to enable the detecting node to obtain the reachable path information, the subsequent detecting node can obtain the reachable path information by manual configuration. For example, the address information of the intermediate node is manually configured in the header node and sent to the subsequent detection node in the response request message, so that the detection node can find the address information of the reachable intermediate node, and then implement the relay response of the response response message. .

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program instructing the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. The invention is not limited to any specific form of combination of hardware and software.

It is a matter of course that the invention may be embodied in various other forms and modifications without departing from the spirit and scope of the invention.

Industrial and practical

In the foregoing technical solution, when the node responds to the response request of the LSP Ping, and there is no reachable route of the head node, the address list information carried in the request packet can be found on the LSP through which the packet passes. The other nodes transmit the response response message to the head node in a relay manner, thereby improving the success rate of the tracking route. Therefore, the present invention has strong industrial applicability.

Claims

1. A method for implementing path detection, comprising:

The detecting node that receives the response request message checks whether the node address in the address list information carried in the response request message is reachable, and uses the found reachable address as the destination address of the response response message; The address information of the node is added to the address list information, and the response response >3⁄4 text carrying the address information of the node is sent to the destination address.

The implementation method of claim 1, wherein the step of the sending node sending a response request carrying the address list information to the detecting node includes:

The implementation method of claim 2, wherein the step of the sending node sending the response request carrying the address list information to the detecting node includes:

The implementation method of claim 1, wherein the step of checking whether the node address in the address list information carried in the response request message is reachable comprises: searching for the response request message in order from the first address Whether the node address in the carried address list information is reachable.

The implementation method of claim 4, wherein the step of using the found reachable address as the destination address of the response response message comprises:

The first reachable address found is the destination address of the response reply message.

6. The implementation method of claim 1, further comprising: The detecting node that receives the response response message checks whether the node address in the address list information carried in the response response message is reachable, and updates the destination address of the response response message to the found reachable address, to the destination. The address sends the response response message carrying the address list information.

The implementation method of claim 6, wherein the step of checking whether the node address in the address list information carried in the response response message is reachable includes:

The address of the node in the address list information carried in the response response message is searchable in order from the first address.

The implementation method of claim 7, wherein the step of updating the destination address of the response response message to the found reachable address comprises:

The implementation method according to any one of claims 1 to 8, wherein the step of the detecting node adding the address information of the node to the address list information comprises:

10. The implementation method of claim 1, wherein all address list information is encapsulated in a TLV form.

11. The implementation method according to claim 1, wherein all addresses in the address list information are loopback addresses.

The implementation method according to any one of claims 1 to 8, wherein the initiating node is a head node of a label switching path LSP, and the detecting node includes the LSP except the head node. Other nodes.

13. A path detection node, comprising a request message sending module, a lookup module, and a reply module, wherein:

The locating module is configured to: when the node is a detecting node, check whether the node address in the address list information carried in the received response request message is reachable, and the reachable location to be found is The address is the destination address of the response response message;

The reply module is configured to: when the node is used as a detection node, add the address information of the node to the address list information, and send a response response message carrying the address information of the node to the destination address.

The node according to claim 13, wherein the request message sending module is configured to send a response request message carrying the address list information to the detecting node in the following manner:

When the n+1th response request message is sent, it is determined that if the node receives the response response message fed back by the destination node of the nth response request message, the device carries the message in the (n+1)th response request message. In response to the address list information in the response message; if the node does not receive the response response message fed back by the destination node of the nth response request message within the predetermined time, then in the n+1th response request message The address list information in the nth response request message is carried.

The node of claim 13, wherein the searching module is configured to check whether the node address in the address list information carried in the response request message is reachable according to the following manner: Whether the node address in the address list information carried in the request packet is reachable.

The node according to claim 15, wherein the searching module is configured to use the following method to find the reachable address as a response to the destination address of the message:

The first reachable address found is the destination address of the response response.

The node of claim 13, the node further comprising a forwarding module, wherein: the forwarding module is configured to: after the node receives the response response message, check the address carried in the response response message Whether the node address in the list information is reachable, the destination address of the response response message is updated to the found reachable address, and the response response carrying the address list information is sent to the destination address.

The node of claim 17, the forwarding module is configured to check whether the node address in the address list information carried in the response response message is reachable according to the following manner: The address of the node in the address list information carried in the response response message is searchable in order from the first address.

The node according to claim 18, wherein the forwarding module is configured to update the destination address of the response response message to the found reachable address by using the following formula:

The node according to any one of claims 13 to 19, wherein the reply module is configured to add the local node address information to the address list information in the following manner:

The node according to any one of claims 13 to 19, wherein the initiating node is a head node of a label switched path LSP, and the detecting node includes other than the head node on the LSP. node.